Just dropped $772 at the dealer for 2 new plugs and 2 coils shorted out by water "mysteriously" collecting in the spark plug wells. Dealer claims there are no leaks but now my Prius is sporting a shiny new bead of caulk on the cowl seam - dead center and directly over the failed coils and plugs - exactly where the tidal wave of water from the well under the passenger wiper cascades into after making a right turn. Coincidence? Dealer claims that caulk was a TSB for water entering cabin, not engine bay. Anyone else seen this, or know the TSB# for the cowl caulk?
Having changed my plugs and wondering what genius designed that layout, and hoping water never got on there I feel your pain, I'd also start peppering toyota with phone calls for my money back
There was a TSB on the '04s that required a bit of weather stripping along the engine cowl b/c of water getting on the ICE, but I assumed that had been long ago fixed/addressed.
The TSB was definitely for water dripping upon the engine head, and the cure was to caulk the center cowl seam. If you do a search you may be able to locate the TSB as I recall posting that in the past, but I don't have access to my TSB library right now.